Microsoft Word is a proprietary word processor designed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS (1983), the Apple Macintosh (1984), the AT&T Unix PC (1985), Atari ST (1986), SCO UNIX, OS/2, and Microsoft Windows (1989). It is a component of the Microsoft Office software system; it is also sold as a standalone product and included in Microsoft Works Suite. The current versions are Microsoft Office Word 2010 for Windows and Microsoft Office Word 2011 for Mac.